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Allogeneic hematopoietic SCT is an effective treatment in accelerated (AP) or blast phase (BP) CML. Imatinib (IM) has transient but significant activity in advanced phases of CML, which may permit early allografting for responding patients. To identify prognostic factors in allograft recipients previously treated with IM, we analyzed 449 allogeneic hematopoietic SCTs performed from 1999 to 2004 in advanced-phase CML, using the data reported to the Center for International Blood and Marrow Transplant Research. CML patients in second chronic phase (CP2, n=184), AP (n=185) and BP (n=80) received HLA-identical sibling (27%), related (3%), or matched or mismatched unrelated donor (70%), peripheral blood (47%) or BM (53%) hematopoietic SCT after myeloablative (78%) or non-myeloablative (22%) conditioning. In all, 52% in CP2, 49% in AP and 46% in BP received IM before hematopoietic SCT. Disease-free survival was 35-40% for CP2, 26-27% for AP and 8-11% for BP. Cumulative incidence of acute and chronic GVHD and TRM were not affected by the stages of CML or pre-hematopoietic SCT IM exposure. Multivariate analyses showed that conventional prognostic indicators remain the strongest determinants of transplant outcomes. In conclusion, there are no new prognostic indicators of the outcomes of allogeneic hematopoietic SCT for advanced-phase CML in the IM era.

Increasing numbers of allogeneic hematopoietic stem cell transplantation (allo-SCT) are being performed for patients who have failed a previous allogeneic or autologous SCT. We investigated whether the EBMT risk score could predict outcome after a subsequent allo-SCT. We analyzed prognostic factors in 124 consecutive patients who underwent a second transplantation using an allogeneic donor at our institution. Patients with either a first autologous (N = 64) or first allogeneic (N = 60) SCT were included. Age, disease stage, time interval from diagnosis to transplantation, donor type, and donor-recipient sex combination were used to establish a score from 0 to 7 points, from which 3 groups were identified. The 5-year survival probability decreased from 51.7% for risk scores 0-3 (low, n = 25), to 29.3% for risk score 4 (intermediate, n = 42), and only 10.4% for risk scores 5-7 (high, n = 57), P = .001. We propose that the EBMT risk score can identify patients most likely to benefit from a second transplantation., (Copyright © 2012 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Last year marked 30 years of hematopoietic stem cell transplantation as a curative treatment of chronic myeloid leukemia (CML). Initially studies used stem cells from identical twins but techniques rapidly developed to use cells first from HLA-identical siblings and later unrelated donors. During the 1990s CML became the most frequent indication for allogeneic transplantation worldwide. This, together with the relative biologic homogeneity of CML in chronic phase, its responsiveness to graft-versus-leukemia effect and the ability to monitor low level residual disease placed CML at the forefront of research into different strategies of stem cell transplantation. The introduction of BCR-ABL1 tyrosine kinase inhibitors during the last decade resulted in long-term disease control in the majority of patients with CML. In those who fail to respond and/or develop intolerance to these agents, transplantation remains an effective therapeutic solution. The combination of tyrosine kinase inhibitors with transplantation is an exciting new strategy and it provides inspiration for similar approaches in other malignancies.

Outstanding results have been obtained in the treatment of chronic myeloid leukemia (CML) with first-line imatinib therapy. However, approximately 35% of patients will not obtain long-term benefit with this approach. Allogeneic hematopoietic stem cell transplantation (HCT) is a valuable second- and third-line therapy for appropriately selected patients. To identify useful prognostic indicators of transplantation outcome in postimatinib therapeutic interventions, we investigated the role of the HCT comorbidity index (HCT-CI) together with levels of C-reactive protein (CRP) before HCT in 271 patients who underwent myeloablative HCT for CML in first chronic phase. Multivariate analysis showed both an HCT-CI score higher than 0 and CRP levels higher than 9 mg/L independently predict inferior survival and increased nonrelapse mortality at 100 days after HCT. CML patients without comorbidities (HCT-CI score 0) with normal CRP levels (0-9 mg/L) may therefore be candidates for early allogeneic HCT after failing imatinib.

PURPOSE Allogeneic hematopoietic cell transplantation (HCT) is curative therapy for chronic myeloid leukemia (CML), but its long-term outcomes are not well described. We studied the long-term outcomes of CML patients in first chronic phase who receive an allogeneic HCT. PATIENTS AND METHODS Our study included 2,444 patients who received myeloablative HCT for CML in first chronic phase between 1978 and 1998 and survived in continuous complete remission for at least 5 years (median follow-up, 11 years; range, 5 to 25 years). Donor sources were human leukocyte antigen-matched siblings in 1,692 patients, unrelated donors in 639 patients, and other related donors in 113 patients. RESULTS Overall survival rates at 15 years were 88% (95% CI, 86% to 90%) for sibling HCT and 87% (95% CI, 83% to 90%) for unrelated donor HCT. Corresponding cumulative incidences of relapse were 8% (95% CI, 7% to 10%) and 2% (95% CI, 1% to 4%), respectively. The latest relapse was reported 18 years post-HCT. In multivariable analyses, history of chronic graft-versus-host disease increased risks of late overall mortality and nonrelapse mortality but reduced risks of relapse. In comparison with age-, race-, and sex-adjusted normal populations, the mortality of HCT recipients was significantly higher until 14 years post-HCT; thereafter, mortality rates were similar to those of the general population (relative mortality ratio at 15 years, 2.3; 95% CI, 0 to 4.9). CONCLUSION Recipients of allogeneic HCT for CML in first chronic phase who remain in remission for at least 5 years have favorable subsequent long-term survival, and their mortality rates eventually approach those of the general population.

Disease stage and recipient/donor human leukocyte antigen (HLA) matching are important determinants of outcome in transplantation using volunteer-unrelated donors (VUD). Matching for HLA-A, -B, -C, -DRB1, -DQB1 is beneficial, whereas the importance of DPB1 matching is more controversial. The impact of HLA matching status may differ dependent on disease stage. We investigated the outcome according to the degree of HLA matching at 6 loci, in 488 recipients of predominantly T-cell depleted bone marrow VUD transplants for leukaemia. Survival was significantly better in 12/12-matched transplants in those with early leukaemia (5 years: 63 versus 41% in 10/10 matched, P=0.006), but not late stage disease. Conversely, within the HLA-mismatched group (< or =9/10), there was a significant survival advantage to DPB1 mismatching (5 years: 39 versus 21% in DPB1 matched, P=0.008), particularly in late leukaemia (P=0.01), persisting in multivariate analysis (odds ratio 0.478; 95% confidence interval 0.30, 0.75; P=0.001). These novel findings suggest that the best outcome for patients with early leukaemia, with a 10/10-matched donor, is achieved by matching for DPB1. Conversely, our results suggest that in patients receiving an HLA-mismatched graft, the outcome is significantly better if they are also mismatched for DPB1. We recommend validation of these results in independent datasets.

Whereas until 2000 allo-SCT was the recommended treatment for all new patients with CML who were eligible on grounds of age and donor availability, approaches to initial therapy have changed very substantially since the introduction of imatinib mesylate. Today topical questions are (1) Should any newly diagnosed patient receive SCT as primary therapy? (2) How should imatinib failure be defined? (3) Should a patient who has failed imatinib but is still in chronic phase be offered an SCT or further treatment with a 'second-generation' TKI? (4) Would prior treatment with imatinib or concomitant delay to transplant adversely affect the subsequent results of allo-SCT? (5) Once the decision to proceed with allo-SCT is taken, how exactly should this be performed? (6) If a patient relapses after allo-SCT, how should he/she be treated? These questions will be addressed, but definitive answers may not yet be possible.

Disease relapse is a major cause of treatment failure after reduced-intensity allografts and while donor lymphocyte infusions (DLIs) can be effective salvage therapy they are associated with severe graft-versus-host disease (GVHD) when administered early after transplantation. We have therefore examined whether imatinib mesylate can delay relapse and postpone the requirement for DLI in 22 patients with chronic myeloid leukemia (CML) allografted using a reduced-intensity regimen. Imatinib was commenced on day + 35 and continued until 1 year after transplantation. Posttransplantation imatinib was well tolerated and abolished the risk of relapse during this period. Twenty-one patients completed 11 months of imatinib therapy, 15 of whom subsequently relapsed and received DLI. Ten patients to date have achieved molecular remission after DLI. Adjunctive targeted therapy allows the kinetics of disease relapse after a reduced-intensity allograft to be manipulated and represents a novel strategy by which outcome may be improved in patients who undergo transplantation for CML and other leukemias.

The discovery and approval of imatinib drastically changed the therapeutic algorithm for chronic myeloid leukaemia (CML). Imatinib is now considered the therapy of choice for patients with newly diagnosed CML, including those previously considered candidates for allogeneic haematopoietic cell transplantation (HCT). We compared numbers and types of allogeneic HCTs performed for CML in North America before and after the introduction of imatinib, and publication of the International Randomized Trial of Interferon and STI571 (IRIS) using transplants reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). The number of HCTs for CML registered with the CIBMTR in 1998 was 617; 62% were performed in first chronic phase (CP1). Only 1% of patients had received imatinib prior to transplantation. In 2003, the number of HCTs reported was 223; 44% were performed in CP1 and 77% of patients received imatinib prior to transplantation. The introduction of imatinib therapy has had a profound impact on the use of allogeneic transplantation for CML, with a marked decrease in the number of transplants for CML and an accompanying decrease in the proportion done in CP1. Most patients now receive a trial of imatinib before proceeding to HCT.

The osteoprotegerin (OPG)/receptor activator of NF-kappa B ligand (RANKL) system has a major role in the pathogenesis of bone disease in myeloma (MM). The effect of autologous stem cell transplantation (ASCT) on bone turnover in MM was evaluated in 51 patients (35M/16F). Markers of bone resorption (NTX, TRACP-5b), bone formation (bone-alkaline phosphatase (bALP), osteocalcin), OPG and sRANKL were measured pre- and every month post-ASCT. The median follow-up period was 12 months. Four patients were transplanted in CR, 44 were transplanted in PR and three patients had progressive/resistant disease. All patients received bisphosphonates both pre- and post-ASCT. At baseline the majority of patients had increased NTX, TRACP-5b levels, and sRANKL/OPG ratio, while markers of bone formation were strongly suppressed. ASCT produced a significant reduction of sRANKL/OPG ratio, with a concomitant decrease of NTX, and TRACP-5b levels, starting the second month post-ASCT. Bone formation markers, osteocalcin and bALP, started to increase after the 9th and 11th month post-ASCT, respectively, while the increase of OPG preceded this. These results provide biochemical evidence that ASCT normalizes the abnormal bone resorption in MM patients possibly through the decrease of RANKL/OPG ratio, while bone formation requires a longer period to return to normal.

The importance of matching for HLA-DPB1 in unrelated donor haematopoietic stem cell (HSC) transplantation is little understood. Most transplant centres do not, currently, prospectively match for DPB1, but emerging data show that DPB1 matching does play a role in determining outcome. We studied the impact of HLA-DPB1 matching on outcome in 143 recipients of T-cell depletion transplants, who matched with their respective unrelated donors (allelic level) at HLA-A, -B, -C, -DRB1 and -DQB1. Of those matched at DPB1, 47.2% (17/36) developed acute graft-versus-host disease (aGvHD) as compared to 66.3% (55/83) of those who were mismatched. This led to a 19.1% (95% CI 0.1-38.3%) increase in the chance of developing aGvHD in mismatched patients (P=0.049). Relapse of the original disease occurred in 51 recipients; 23 of 37 (62%) matched at both DPB1 alleles, 28 of 82 (34%) were mismatched at one or two DPB1 alleles. Thus, there was a significantly higher relapse rate (P=0.0011) in transplant recipients who matched at both DPB1 alleles. In conclusion, a donor/recipient DPB1 match was associated with a significantly lower incidence of aGvHD and a significantly higher incidence of disease relapse. This study provides further evidence for an immunogenic role of HLA-DPB1 in HSC transplants.

Leukemia is a disease characterized by the malignant transformation of hematopoietic stem cells. Previous studies have shown that the Wilms' tumor antigen-1 (WT1) transcription factor is expressed at elevated levels in hematopoietic stem cells of leukemia patients compared with normal stem cells. In the past, we have generated cytotoxic T lymphocytes (CTL) specific for WT1, and we have shown that they killed WT1-expressing leukemia cell lines and inhibited the in vitro colony-forming activity of leukemia cells of patients. We used a xenotransplantation model to address whether WT1-specific CTL can selectively inhibit engraftment of malignant but not normal stem cells. CD34+ hematopoietic cells isolated from individuals with chronic myeloid leukemia or normal hematopoiesis were treated with WT1-specific CTL and injected into immunodeficient non-obese diabetic-severe combined immunodeficient mice. After 5 to 8 weeks, engraftment of leukemic or normal human cells was analyzed using immunohistology, flow cytometry, and polymerase chain reaction amplification of human sequences. The data showed that exposure of chronic myeloid leukemia CD34+ cells to WT1-specifc CTL completely prevented the development of leukemia in the recipient mice, whereas CTL treatment did not inhibit engraftment of normal CD34+ stem cells. The experiments indicate that WT1-specific CTL can discriminate between stem cells that give raise to leukemia and normal hematopoiesis in the xenogenic transplantation model. This supports the use of CTL with this specificity for treatment of leukemia patients undergoing stem-cell transplantation.

We have analysed the outcome of 581 autologous stem cell transplants (SCT) for chronic myeloid leukaemia (CML) in first chronic phase reported to the European Group for Blood and Marrow Transplantation between 1983 and 1998. Out off 207 patients evaluable for cytogenetics within 6 months of SCT, 36 patients (17%) were in complete cytogenetic remission (CCR), 34 (16%) in major remission (MCR), 74 (36%) in minor remission (mCR) and 63 (31%) had no cytogenetic response (NR). Interferon (IFN) was given post SCT to 267 patients. Results of the cytogenetic analysis within 1-2 years from SCT were available for 117 patients, the majority of whom (n = 101) received IFN post SCT: 17 (15%) were in CCR, 18 (15%) in MCR, 24 (20%) in mCR and 58 (50%) NR. The median survival in this series was 96 months (71-125) from SCT. There was no difference in survival according to cytogenetic status pre- and immediately post SCT. However, patients in CCR or MCR at 1-2 years post SCT had a 10-year survival of 66% compared with 36% for patients in mCR or NR (P = 0.003). The 5-year survival for patients receiving IFN post SCT was 72% compared with 61% for patients not treated with IFN (P = 0.01). Out of 155 patients refractory to IFN pre SCT, 70% achieved a cytogenetic response post SCT, which was complete or major in 31%. IFN refractory patients who sustained a CCR or MCR for 1-2 years after SCT had an excellent outcome.

Donor lymphocyte infusion (DLI) can restore durable molecular remission in a high percentage of patients with chronic myeloid leukemia (CML) who have relapses after allogeneic stem cell transplantation, but for patients who do not respond survival is poor. Imatinib mesylate (STI571) is a specific inhibitor of BCR-ABL tyrosine kinase that can induce hematologic and cytogenetic remissions in patients with CML. We report here a male patient who had a relapse to chronic phase after stem cell transplantation for CML, did not benefit from treatment with DLI, and then was administered STI571 at a dose of 400 mg daily. There was a rapid, complete hematologic response, and complete restoration of donor-type hematopoiesis (100% 46, XX marrow metaphases) was achieved after 6 months of therapy, though RT-PCR studies still detected BCR-ABL transcripts in the blood at low level. This case demonstrates that imatinib mesylate can be highly effective in the management of patients who have relapses after allograft for CML.

We identified 103 consecutive patients who, 5 years after allogeneic transplantation for chronic myeloid leukaemia (CML), were in molecular remission (MR). The 103 patients were divided into three groups on the basis of reverse transcription-polymerase chain reaction (RT-PCR) studies for BCR-ABL transcripts in the first 5 years post transplant: Group A comprised 63 patients who had been continuously PCR negative; Group B comprised 20 patients with one or more positive PCR result but only at a low level; and Group C comprised 20 patients who had fulfilled the criteria for molecular relapse, been treated with donor lymphocyte infusions (DLI) and had thereafter regained complete MR within the 5-year post-transplant period. The median follow-up for all 103 patients was 8.4 years from transplant (range 5-17.6 years). In group A only one patient relapsed at 9.2 years. In group B eight patients (40%) relapsed: six at molecular, one at cytogenetic and one haematological levels. The actuarial probabilities of survival at 10 years for patients in Groups A, B and C were 97.4%, 92.9% and 100% respectively; the probabilities of relapse were 3%, 54% and 0% respectively. We conclude that molecular studies during the first 5 years post transplant can help to predict long-term leukaemia-free survival and, possibly, cure of CML.

A case of immune neutropenia following unrelated stem cell transplantation for chronic myeloid leukaemia is described. The neutropenia developed following herpes zoster viral infection and was associated with antibodies to the human neutrophil antigen (HNA)-2a (formerly known as NB1). The neutropenia was prolonged, profound and unresponsive to granulocyte colony-stimulating factor (GCSF). The neutrophil count recovered after GCSF was discontinued. HNA-2a has been reported to be upregulated following GCSF administration. In the present case, it appears that the immune neutropenia may have been perpetuated by GCSF administration.

The reverse transcriptase-polymerase chain reaction (RT-PCR) has become widely used for monitoring minimal residual disease after allogeneic stem cell transplantation (SCT) for chronic myeloid leukemia (CML). However, most of these studies were performed using qualitative RT-PCR, and the interpretation of the results obtained has been conflicting. The correlation of a quantitative RT-PCR test performed early after SCT (at 3 to 5 months) and long-term outcome of CML patients surviving for more than 6 months was studied. Between January 1991 and June 1999, data from 138 CML patients who received allografts were evaluated. Early RT-PCR results were classified as (1) negative if there were no BCR-ABL transcripts detected (n = 61), (2) positive at low level if the total number of BCR-ABL transcripts was less than 100 per microg RNA and/or the BCR-ABL/ABL ratio was less than 0.02% (n = 14), or (3) positive at high level if transcript levels exceeded the thresholds defined above (n = 63). Three years after SCT the cumulative incidence of relapse was 16.7%, 42.9%, and 86.4%, respectively (P =.0001). The relationship between BCR-ABL transcript level and probability of relapse was apparent whether patients had received sibling or unrelated donor SCT and also whether or not the transplantation was T cell depleted. The results suggest that quantitative RT-PCR performed early after SCT is useful for predicting outcome and may help to define the need for further treatment.

Graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality after haematopoietic stem cell transplantation from matched unrelated donors (MUD). The role of T-cell depletion (TCD) as a strategy to prevent GVHD is controversial because of the associated increased risk of leukaemic relapse, graft failure and delayed immune reconstitution. The demonstration that donor lymphocyte infusion (DLI) is effective salvage therapy if patients relapse after transplantation for chronic myeloid leukaemia (CML) prompted us to examine the proposal that TCD may be a form of GVHD prophylaxis particularly suited to this disease in patients undergoing MUD transplantation. We analysed the outcome of 106 consecutive patients with CML in first chronic phase who underwent MUD transplantation. Patients were conditioned with cyclophosphamide and total body irradiation (TBI), and received in vivo TCD, using CD52 monoclonal antibody, as GVHD prophylaxis. Donor lymphocytes were infused at the time of leukaemic relapse. The projected survival at 5 years for all patients was 52.6%. The probability of developing severe acute GVHD (grade 3 or 4) was 14.5%. The only significant predictor of overall survival in univariate and multivariate analysis was patient cytomegalovirus (CMV) serostatus: in CMV-negative patients survival at 5 years was 60% vs. 42% in CMV-positive patients (P = 0.006). The use of TCD was associated with an increased risk of relapse (62% probability at 5 years after transplant), but 80% of patients who received DLI achieved molecular remission that was durable in all but two cases. In vivo TCD, in conjunction with DLI at relapse, is a valuable GVHD prophylactic regimen in CMV-seronegative recipients of MUD allografts, but in CMV-seropositive patients this approach is associated with an increased non-relapse mortality. Consequently, GVHD prophylactic regimens in MUD transplantation should be tailored according to the patient and donor pretransplant characteristics.

An analysis was performed of the response to treatment with donor lymphocyte infusions (DLI) and the survival in 66 consecutive patients who relapsed after primary treatment by allogeneic stem cell transplantation for BCR-ABL-positive chronic myeloid leukemia. The transplant donor was an HLA-identical sibling (n = 35) or a "matched" unrelated volunteer (n = 31). Fifty-seven patients were transplanted in chronic phase, eight in accelerated phase, and one in second chronic phase. The recognition of relapse was based on precise molecular, cytogenetic, or hematologic criteria. The median interval from transplant to relapse was 12 months (range 3-85). The median interval from relapse to initiation of DLI was 9.4 months (range 1-70). Patients received DLI from their original transplant donors on a bulk-dose (n = 34) or on an escalating-dose (n = 32) regimen. Patients were monitored serially by hematologic, cytogenetic, and molecular criteria. Molecular remission was defined by the finding of negative results by nested primer reverse transcriptase polymerase chain reaction (RT-PCR) for BCR-ABL transcripts on two consecutive occasions, subject to satisfactory controls. Forty-four patients (67%) achieved molecular remission. Patients who had relapsed to advanced phase disease and patients with short intervals between transplant and relapse had significantly lower probabilities of achieving molecular remission. Of the 44 patients who achieved molecular remission, 4 reverted to a PCR-positive status at 15, 18, 37, and 87 weeks after remission. The probability of survival for patients who achieved molecular remission was significantly better than for those who failed to do so (95% versus 53% at 3 years post-DLI, P = .0001). We conclude that the majority of molecular remissions after DLI are durable, and thus the majority of responding patients may prove to have been cured. (Blood. 2000;96:2712-2716)

A significant number of patients who relapse after allogeneic stem cell transplantation (SCT) for chronic myeloid leukemia (CML) will achieve sustained remissions after treatment with interferon-alpha, second transplants, or donor lymphocyte infusions (DLI) from the original stem cell donor. Because leukemia-free survival (LFS) is at present defined as survival without evidence of relapse at any time posttransplant, patients who relapse but are then restored to complete remission are treated as failures when estimating LFS. We have established a new category of LFS, termed current LFS (CLFS), which we define as survival without evidence of leukemia at the time of most recent assessment. To gauge the contribution of treatment for relapse to the efficacy of allogeneic SCT in the management of CML in chronic phase, we compared conventional LFS and CLFS in 189 consecutive patients who underwent SCT over a 7-year period with a minimum follow-up of 3 years. Patients with sibling donors (n = 111) received cyclosporine and methotrexate as prophylaxis for graft versus host disease; patients with unrelated donors (n = 78) also received Campath-1G or 1H as intravenous T-cell depletion. The 5-year LFS defined conventionally was 36% (CI: 29% to 43%) versus a 5-year CLFS of 49% (CI: 36% to 62%). This new method of defining LFS confirms the view that appropriate "salvage" therapy, principally DLI, makes a major contribution to the capacity of allogeneic SCT to produce long-term LFS in patients who receive SCT for CML and emphasizes the importance of redefining LFS to take account of successful treatment of relapse.

Peripheral blood cells are increasingly used in place of bone marrow as a source of hematopoietic stem cells for allogeneic transplantation. The relative efficacy of these 2 approaches is unknown. This retrospective multivariate analysis compared results of 288 HLA-identical sibling blood stem cell transplantations with results of 536 HLA-identical sibling bone marrow transplantations. No transplants were T-cell depleted. Median follow-up was 12 months, and analyses focused on 1-year outcomes. Recipients of blood stem cell transplants had more rapid recovery of neutrophils to at least 0.5 x 10(9)/L (median time to recovery, 14 days, compared with 19 days for marrow transplants; P <.001) and of platelets to at least 20 x 10(9)/L (median time, 18 days, compared with 25 days for marrow transplants; P <.001). There was no significant difference in the incidence of grades II to IV acute graft versus host disease (GVHD). The incidence of chronic GVHD was significantly higher after blood stem cell transplantation (1-year probability [95% confidence interval], 65% [56%-72%] compared with 53% [47%-59%]; P =.02) Relapse incidence in the 2 transplant groups did not differ significantly. Treatment-related mortality rates were lower and leukemia-free survival rates were higher with blood stem cell transplants in patients with advanced leukemia (acute leukemia in second remission or chronic myelogenous leukemia in accelerated phase) but not in early leukemia (acute leukemia in first remission or chronic myelogenous leukemia in chronic phase). The median time from transplantation to hospital discharge was 23 days after blood stem cell transplantation and 28 days after bone marrow transplantation (P =.003). Further study with longer follow-up is necessary to definitively establish the role of blood stem cells for allogeneic transplantation, especially in patients with good-risk disease. (Blood. 2000;95:3702-3709)

A significant number of patients who relapse after allogeneic stem cell transplantation (SCT) for chronic myeloid leukaemia (CML) will achieve sustained molecular remissions after treatment with donor lymphocyte infusions (DLI) from the original stem cell donor. Leukaemia-free survival, defined as survival without evidence of relapse at any time after transplant does not account for patients who are successfully treated with DLI. To summarize adequately the response to treatment, a new summary probability, called the current leukaemia-free survival (CLFS), is proposed. This quantity is defined as the probability that a patient is alive and in remission at a given time after transplant. We discuss two statistical methods for estimating CLFS. The first is based on a multistate modelling approach. The second is based on an estimate constructed by looking at appropriate differences between Kaplan-Meier estimates. We compare these estimates using data on 189 consecutive patients who underwent SCT over a 7-year period.

Introduction: Chronic myelogenous leukemia is characterized by a clonal expansion of abnormal hematopoietic cells, which eventually replaces normal hematopoiesis. We wanted to test the hypothesis that the growth kinetics of CML and normal hematopoietic cells are different., Materials and Methods: We compared the growth kinetics and the phenotype of engraftment of chronic phase CML and normal human CD34(+) precursor cells in the bone marrow of immune deficient mice., Results: High levels of engraftment of normal precursors occurred early and consisted of myeloid, erythroid, megakaryocytic, and lymphoid elements. This level and pattern of engraftment were maintained at later assessments. The level of CML cell engraftment was initially much lower, but it increased progressively at late time-points with no indication of a plateau in growth. Early engraftment of CML cells consisted almost entirely of myeloid and mast cells but soon after only mast cells were detectable. Conversely mast cells were infrequent in mice engrafted with normal progenitors., Conclusion: We conclude that in contrast to normal cell engraftment, engraftment of CML cells in NOD/SCID mice is characterized by a slow but progressive myeloid infiltration, which eventually consists almost entirely of mast cells.

The infusion of lymphocytes from the original marrow donor (donor lymphocyte infusion [DLI]) reinduces complete remission in a high percentage of patients with chronic myeloid leukemia (CML) who relapse after allogeneic stem cell transplant, and thus, is probably the best initial approach to their management. The major predictive factor for response is the disease stage at time of treatment, because patients in molecular or cytogenetic relapse fare better than those in hematologic relapse. Moreover, patients with a short interval between transplant and DLI have a higher probability of response than those with longer intervals. The durability of DLI-induced remissions has not yet been established, but they appear to be prolonged. The observation that DLI can be highly effective for patients in relapse has encouraged the recent development of new strategies designed to minimize the myeloablative regimen and exploit the immunotherapeutic component of the transplant. The principal complication associated with use of DLI is the occurrence of graft-versus-host disease (GVHD). Several approaches have been tested to reduce the incidence or impact of GVHD, based on the ex vivo depletion of alloreactive donor cells or the use of donor T cells transduced with a suicide gene. The incidence of GVHD can also be reduced by starting with low doses of donor cells and "escalating" subsequent doses as required. However, the identification of selective targets for leukemia-reactive immunity is probably the optimal strategy to resolve the problem of GVHD. Although currently minor histocompatibility antigens appear to be the most likely targets for DLI, several groups are focusing on the generation of leukemia-specific immunity. The results obtained by use of tumor-associated antigens presented by dendritic cells are encouraging and may lay the foundations for the use of adoptive immunotherapy in the autologous setting.

Some of the factors that may influence the number and quality of cord blood haematopoietic progenitor cells available for transplantation have been investigated including site of collection, delayed processing after collection and cryopreservation protocol. We used the granulocyte-macrophage progenitor (CFU-GM) and erythroid burst-forming unit (BFU-E) assays to quantify progenitors. The capacity of CFU-GM to produce secondary colonies was used as a measure of progenitor cell quality. We found that: (1) there were no significant differences in total nucleated cells (TNC), mononuclear cells (MNC), CFU-GM or BFU-E numbers in paired specimens from the umbilical vein or veins at the base of the placenta. The potential of the CFU-GM to produce secondary colonies from the two sites was similar; (2) storing cord blood at room temperature or at 4 degrees C resulted in a significant reduction in progenitor cell numbers beyond 9 h; and (3) cryopreservation following either controlled rate freezing or passive cooling reduced MNC numbers, viability and CFU-GM survival insignificantly but the potential of CFU-GM to produce secondary colonies was significantly reduced post cryopreservation (P = 0.04). We conclude that the yield of CB progenitor cells is not affected by the site of collection, but is adversely affected by delays between collection and cryopreservation. Furthermore, cryopreservation reduced the CFU-GM potential to produce secondary colonies. Measures of progenitor cell quality as well as quantity may be relevant to assessing CB blood collections.

We investigated the impact of maternal and fetal variables on cord blood (CB) haemopoietic stem/progenitor cell content. These included maternal age, ethnic origin, parity, ABO and Rhesus D blood group, antenatal haemoglobin, alcohol and cigarette consumption at time of registration, mode of delivery, duration of the first and second stages of labour, gestational age, birth weight, cord pH and cord erythrocyte mean cell volume (MCV). Cord volumes and total nucleated cellularities (TNC) were recorded, the colony assay for granulocyte-macrophage colony-forming-cells (CFU-GM) was used to quantify the progenitor cells and the potential of CFU-GM to produce secondary colonies on replating was used as a measure of progenitor cell quality. We found: (1) significantly greater (P=0.04) volumes were collected from babies who weighed > or = 2.5kg versus babies with a birth weight <2.5kg; (2) significantly greater numbers of mononuclear cells (MNC) from mothers who drank 0-3 units versus those who drank > or = 4 units of alcohol weekly (P=0.03), and in babies with a cord pH < or = 7.1 v > 7.1 (P=0.02); (3) Significantly greater numbers of cord CFU-GM in mothers who drank 0-3 v > or = 4 units weekly (P=0.004) and smokers of > or = 10 v 0-9 cigarettes daily (P=0.02) and in spontaneous vaginal deliveries than assisted vaginal and caesarean deliveries (P=0.04), and (4) the potential of CFU-GM to produce secondary colonies was significantly greater in CB derived from Caucasians than from non-Caucasians ( P=0.02); in assisted vaginal delivery v spontaneous vaginal (P=0.02) and in deliveries with prolonged first stage of labour v short first stage of labour (P=0.04). We conclude that antenatal and perinatal variables may influence the CB stem/progenitor cell yield available for transplantation.

A questionnaire was mailed to a senior haematologist in each of 31 countries to investigate the current use of G-CSF for PBSC mobilisation in normal healthy donors. The questions related to the regulatory status of G-CSF, its use in the related and unrelated donor settings, whether a national standardised protocol had been developed, which routes of vascular access were permitted, whether self-administration of G-CSF was allowed, strategies for monitoring long-term after-effects of the use of G-CSF and the approximate numbers of donors who had received G-CSF in each country during 1996. Responses were received from 28 countries. Clinicians in all 28 countries are administering G-CSF to related donors, and in nine countries also to unrelated donors; the situation vis-à-vis unrelated donors is under review in another 11 countries. Responses indicate that approval for the use of G-CSF has come mainly through local research ethics committees. Of those countries permitting the use of G-CSF in the unrelated donor setting, six permit it for second donations, two for both first and second donations, and one in a limited trial situation only. In just one of these nine countries has a national standardised protocol been developed. Self-administration of G-CSF by donors is allowed in 18/27 countries. Venous access is restricted to peripheral veins in 10/28 countries, the remaining 18 permit central venous access if peripheral access fails. Regarding the number of normal donors receiving G-CSF during 1996, Germany, Israel, Italy and Spain report more than 100 each, Canada, The Netherlands, South Africa, and the UK report in the range 31-100, and the remaining responding countries each report under 30 donors. Methods for long-term follow-up vary considerably from country to country and involve questionnaires and/or medical examinations, with less than half the responders specifying the need for laboratory investigations.

Allogeneic stem cell transplantation is the only curative therapy for chronic myeloid leukemia. There have been several recent advances in this field. Early data suggest that blood-derived stem cells are an effective substitute for bone marrow. Allografting can be performed using progenitor cells from other family members, unrelated donors, and umbilical cord blood. Evidence of early relapse can be detected by assays for the fusion gene, BCR-ABL, using the polymerase chain reaction. Most patients who relapse following allogeneic stem cell transplantation can be treated effectively by transfusion of lymphocytes from their original donors.

Between June 1994 and October 1995 we performed 11 autografts in nine patients with advanced-phase chronic myeloid leukaemia (CML) using an attenuated cytoreductive regimen consisting of busulphan 8 mg/kg given in divided doses over 4 d. Five patients were restored to chronic phase. Four patients survived > 50 weeks and one remains well at 79 weeks. Toxicity was generally mild. Four procedures were managed entirely in the out-patient clinic. Therefore autografting after this 'intermediate' dose busulphan provides good palliation for patients with advanced CML with relatively little toxicity. Attenuated autografting should offer major advantages in terms of quality of life and cost for patients with advanced-phase CML.

Information on 17,206 haemopoietic precursor cell transplants performed in 12 European countries between 1991 and 1993 was used to assess the number of transplants per million inhabitants per year by principal indication and donor source. 16.6 transplants were performed per million inhabitants per year with a range of 9.4-27.7. Differences between countries may be due to the availability of beds and resources or to divergent opinions about treatments. We used the coefficient of variation (CV) to assess the degree of agreement between clinicians with regard to different procedures and indications, with a cut-off of < or = 45% to indicate consensus. The rate of allogeneic transplantation between the 12 countries was more 'homogenous' than that of autologous transplantation (mean 6.8 per million inhabitants, range 5.2-9.5, CV 20% versus mean 9.8 per million inhabitants, range 3.6-18.4, CV 40%). Consensus was found for allografting in chronic myeloid leukaemia (CML) in first chronic phase (CV 19%), CML in later phases (CV 31%), acute myeloid leukaemia (AML) in first complete remission (CV 41%), AML beyond first complete remission (CV 34%), acute lymphoblastic leukaemia beyond first complete remission (23%), and severe aplastic anaemia (29%). Consensus for autografting was observed for Hodgkin's disease (CV 44%), non-Hodgkin's lymphoma (CV 44%), and AML beyond first remission (CV 41%). With this method an assessment of medical opinion can be made in spite of the different availabilities of resources. These data reflect the state of the art in haemopoietic precursor cell usage in Europe; they provide a basis for patient counselling and health-care planning.

Between June 1977 and July 1983 51 patients with Ph1-positive chronic granulocytic leukaemia (CGL) in transformation were treated either by chemotherapy or by chemoradiotherapy followed by autografting with haemopoietic stem cells collected from their peripheral blood at the time of diagnosis. Forty-eight patients were restored to a second chronic phase. The median duration of survival after autografting was 26 weeks (range 2-152 weeks). Twenty-one patients with relatively long durations of second chronic phase were treated again by autografting as consolidation or when transformation recurred; this selected group of patients survived longer than the 30 patients treated by autografting only once (medians 52 v. 13 weeks respectively, P less than 0.01). There was no significant influence of the patients' age, splenectomy status, type of transformation, treatment pre-autograft or number of nucleated cells autografted on the duration of survival. Three patients treated in myeloid blastic transformation were restored to partially Ph1-negative haemopoiesis. We conclude that this approach to the management of CGL in transformation can offer benefit for a minority of patients and that further chemotherapy and autografting for patients still in second chronic phase may be valuable.

Bone marrow collected from all species including man contains specific cells, putative pluripotential stem cells, capable of reestablishing hemopoiesis in a syngeneic or genetically identical member of the same species which has been treated with whole body irradiation. The question of whether similar pluripotential stem cells are present in the circulation in all animals is not yet resolved. In mice, reconstitution of hemopoiesis can be achieved by transfusion of peripheral blood cells only. The same result can be obtained in dogs and probably in baboons. In dogs, experiments with fresh and cryopreserved blood mononuclear cells have confirmed a dose-response relationship--below a certain number of mononuclear cells failure of hemopoietic reconstitution can be predicted. In man, isolated anecdotal case reports suggest that pluripotential stem cells in the circulation may or may not be valuable in repopulating a bone marrow defective as a result of primary disease or following chemotherapy. Indirect evidence from in vitro culture of circulating myeloid progenitor cells suggests but does not prove that pluripotential stem cells circulate in normal man. Pluripotential stem cell numbers are probably greatly increased in the circulation in patients with chronic granulocytic leukemia: such cells can be collected, cryopreserved, and used at a later date as "bone marrow autografts". Whether circulating stem cells can be collected and used in an analogous manner for patients with other leukemias or other neoplasms is not yet established.

Two patients with chronic granulocytic leukaemia in blast cell transformation treated with high-dose cytotoxic drugs and transfusion of cryopreserved chronic phase buffy coat stem cells developed a clinical and pathological syndrome that closely resembled graft-versus-host disease (GVHD). It was possible (1) that both patients had true GVHD resulting from transfusion of HLA-identical blood products, or (2) that both cases were examples of the 'pseudo-GVHD' seen by others following syngeneic transplants. The laboratory findings did not support one postulated pathogenetic mechanism for 'pseudo-GVHD'--namely a lack of suppressor T-lymphocytes.

A previously untreated 31-yr old female with Ph-positive chronic myeloid leukaemia (CML) received busulphan and melphalan at high dosage followed by an autograft of peripheral blood stem cells collected 4 weeks earlier. Though recovering haemopoiesis was at first mainly Ph-positive, Ph-negative haemopoiesis predominated at 12 months and has persisted until the most recent study (24 months post-autograft). Her haemopoietic cells now show no rearrangement of the bcr gene, unlike the cells collected at diagnosis. Autografting carried out soon after diagnosis could be valuable for obtaining cytogenetic remissions in other patients with CML.